Electrostatic interaction between a rod-like macromolecule and a circular orifice/disk in an electrolyte solution

We present the solutions of the interaction energy for a colloid system with a charged rod-like macromolecule immersed in a bulk electrolyte and moving along the axis of a circular orifice or disk （orifice/disk）. The calculation requires a numerical computation of the surface charge profiles, which result from a constant surface potential on the macromolecule and the orifice/disk. In the calculation, remarkable divergences of the surface charge emerge on the edges of the macromolecule and the orifice/disk, which are well-known edge effects. The anisotropic distribution of the surface charge （effective dipole） results in an attraction between these two charged objects. This attraction is enhanced with the increase of the screening length of the system for both the orifice and the disk systems. However, the sizes of the orifice and the disk reduce to different effects on the interaction energy.

Investigation into the Deep Drawability of 0.1%C Eutectoid Steel

The phenomenon of anisotropism in most rolled products necessitates that the rolling direction that enhances desirable mechanical property is established. In this paper, the comparative deep drawability of as-received and annealed mild steel containing about 0.1%C was investigated. The flat steel sample was divided into two and classified as as-received and heat treated respectively. The heat treated sample was obtained by annealing at 950°C after been soaked for 5 hours and deep drawn at ambient temperatures (35°C - 42°C). From both samples, circular specimens were machine- blanked parallel to the rolling directions inclined at 0°, 45° and 90° respectively and were prepared for deep drawability test while rectangular specimens were prepared for tensile test. Both specimens, as-received and annealed were then sub- jected to tensile, cupping and microstructural analyses. Results show that the contribution to increased formability at 90° rolling direction seems to have come from the spheroid-like pearlite grains induced during annealing while the sta- bility of spread observed was achieved through a modest increase in strength. Thus, the resistance of annealed eutectoid steel to cupping is quite minimal at 90° to the rolling direction. The desirable drawability characteristics developed by the annealed eutectoid steel specimen are: cup-height, 30 mm maximum and ear, 6.4% maximum.